What is the sensitivity of stress electrocardiograms (ECGs) for diagnosing coronary artery disease (CAD)?

From the Guidelines

Stress electrocardiograms (ECGs) have a sensitivity of approximately 65-70% for diagnosing coronary artery disease (CAD), as indicated by the 2013 ESC guidelines on the management of stable coronary artery disease 1. The sensitivity of stress ECGs for detecting CAD can vary based on several factors, including the severity and extent of coronary disease. Key factors influencing the sensitivity of stress ECGs include:

• Severity and extent of coronary disease, with higher sensitivity for multi-vessel or left main coronary artery disease and lower sensitivity for single-vessel disease
• Patient characteristics, such as age, sex, and presence of baseline ECG abnormalities
• The presence of certain medical conditions, such as left ventricular hypertrophy or left bundle branch block, which can reduce the sensitivity of the test The test works by recording electrical activity of the heart during increasing levels of physical exertion, typically on a treadmill or stationary bicycle, to reveal ischemic changes that may not be apparent at rest. According to the guidelines, exercise ECG testing is not of diagnostic value in the presence of certain conditions, such as LBBB, paced rhythm, and Wolff-Parkinson-White syndrome, in which cases the ECG changes are not interpretable 1. Additionally, false-positive results are more frequent in patients with abnormal resting ECG in the presence of LVH, electrolyte imbalance, intraventricular conduction abnormalities, atrial fibrillation, and use of digitalis 1. To improve diagnostic accuracy, stress ECGs are often combined with imaging modalities like echocardiography or nuclear perfusion studies, which can increase sensitivity to 85-90%. Despite its limitations, stress ECG remains a valuable first-line test for CAD evaluation due to its wide availability, low cost, and ability to provide information about functional capacity and exercise tolerance 1.

From the Research

Sensitivity of Stress Electrocardiograms (ECGs) for Diagnosing Coronary Artery Disease (CAD)

• The sensitivity of stress ECGs for diagnosing CAD is reported to be 42% in a study published in the Journal of the American College of Cardiology 2.
• This study compared the accuracy of dobutamine ECG stress testing with dobutamine two-dimensional echocardiography and technetium-99m methoxyl isobutyl isonitrile (mibi) perfusion scintigraphy.
• The sensitivity of stress ECGs was found to be lower than that of technetium-99m mibi perfusion (76%) and stress echocardiography (76%) 2.
• Other studies have compared the sensitivity of stress echocardiography with myocardial perfusion imaging, with results showing that stress echocardiography has a slightly lower sensitivity for detecting CAD 3, 4.
• The overall sensitivity of stress echocardiography for detecting CAD is reported to be slightly lower than that of single photon emission computed tomography (SPECT) 3.
• However, stress echocardiography has been shown to be more cost-effective than exercise ECG in patients with low-intermediate pre-test probability of CAD 5.

Comparison with Other Modalities

• Stress echocardiography has been compared with other modalities such as myocardial perfusion imaging, stress cardiac magnetic resonance imaging, and coronary computed tomography (CT) angiography 6.
• The choice of modality depends on various factors, including the patient's pre-test probability of CAD, the availability of equipment and expertise, and the patient's individual characteristics 5, 6, 3, 4.